Accelerating Mineral Carbonation Using Carbonic Anhydrase

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• 作者：Ian M. Power ; Anna L. Harrison ; Gregory M. Dipple
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：March 1, 2016
• 年：2016
• 卷：50
• 期：5
• 页码：2610-2618
• 全文大小：540K
• ISSN：1520-5851

文摘

Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO₂) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO₂ and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO₂. This rate limitation can be directly addressed by incorporating enzyme-catalyzed CO₂ hydration. This study examined the effects of bovine carbonic anhydrase (BCA) and CO₂-rich gas streams on the carbonation rate of brucite [Mg(OH)₂], a highly reactive mineral. Alkaline brucite slurries were amended with BCA and supplied with 10% CO₂ gas while aqueous chemistry and solids were monitored throughout the experiments (hours to days). In comparison to controls, brucite carbonation using BCA was accelerated by up to 240%. Nesquehonite [MgCO₃·3H₂O] precipitation limited the accumulation of hydrated CO₂ species, apparently preventing BCA from catalyzing the dehydration reaction. Geochemical models reproduce observed reaction progress in all experiments, revealing a linear correlation between CO₂ uptake and carbonation rate. Data demonstrates that carbonation in BCA-amended reactors remained limited by CO₂ supply, implying further acceleration is possible.